Hammer is a tool to manage big projects that consist of multiple git repositories, which are loosely coupled.
It provides global sync of all managed repositories, global operations for all or a subset of the repositories, and integration with Gerrit Code Review.
The outstanding feature is support for consistent changes in multiple repositories.
On Debian-based systems, install:
$ apt-get install libgit-repository-perl libxml-parser-perl liburi-perl
On Fedora or RHEL you need to install:
$ dnf install perl-Git-Repository-Plugin-AUTOLOAD perl-URI perl-CPAN perl-Test perl-File-pushd perl-XML-Parser
On openSUSE or SLE you need to install:
$ zypper in git make perl perl-base perl-File-pushd perl-Git perl-Pod-Coverage-TrustPod perl-Test-Base perl-Test-Pod perl-Test-Pod-Coverage perl-URI perl-YAML perl-XML-Parser
$ cpan install Git::Repository
On Arch Linux, these packages need to be installed from the AUR by a method of your choice:
$ pacman -S perl-xml-parser perl-uri
$ yay -S perl-git-repository
ham updates many repositories at once in the background, typically using ssh as a secure transport. It is therefore required to use ssh-agent to allow for non-interactive ssh-authentication.